The present invention relates, in general, to a vehicle wheel apparatus and in particular to multi piece vehicle wheels wherein a tire rim is attached to a central hub body.
For quite some time automotive manufacturers and particularly wheel manufacturers have produced two-piece wheel assemblies which have a center hub portion or spider for attachment to the vehicle, within a pneumatic tire rim device. In the past the tire rim and central body have been joined together by various means. The two most widely accepted methods for joining the two wheel components into a single integrated unit have been resistance welding and riveting. Both these methods have been widely used in wheel constructions wherein the outer tire rim component is fabricated of steel, whether the central body is fabricated of steel or various non-ferrous metals.
While the rivet method has good strength properties, there are several drawbacks associated with it. Among these drawbacks is the fact that penetration of both the tire rim and central body portion of the wheel can allow air to leak around the rim attachment, thus affecting the usability of the wheel with a tubeless tire application. Quite often, to guarantee that no air leakage occur when using the rivet method, a self-sealant rivet or protective coating over the standard rivet is applied. While the success of these preventive procedures is quite good, it nontheless drastically increases production costs and is not well accepted.
Resistance welding is the most common method for connecting the outer rim portion and central body portion of the wheel into an integrated, sturdy unit. However, reliability of spot fusion between the rim and the central body portion is often difficult to maintain and inspect. Inherent with the use of the resistance welding method is the need for higher quality control through X-ray or destructive testing. Possible deterioration of the weld could, in some cases, further lead to the undesirability of this particular process, especially in view of the fact that equipment costs and power consumption are extremely high for this mode of fabrication.
Other means for rigidly fusing the pneumatic tire rim component to the wheel center body have included the utilization of steel inserts which are cast into the wheel center body and are welded to the steel rim, such as is disclosed in U.S. Pat. Nos. 3,250,571 and 3,250,572. Additionally, a wheel having a non-ferous metal center body and pneumatic tire rim of malleable metal, has been attached through the use of dimple-like depressions formed in the peripheral ring of the center body by stamping protruberances from the tire rim into the central body to cause a tight fit therewith, as disclosed in U.S. Pat. No. 3,635,529. It is important to note that in this prior art the manner of securing the outer tire rim to the inner wheel center is adaptable primarily to wheels having an outer steel tire rim and an inner non-ferrous metal center, since such a non-ferrous center body portion would have a substantial metal depth around its periphery to accommodate the dimple, towards restraining the rim in its place.
While various attempts have been made in the past to secure a steel rim to a steel spider or center body without the use of rivets or welding, no such prior methods have provided structures capable of production with reliability for strength and function to all the forces acting on the wheel assembly in its total operation and life cycle.
It is thus an object of the present invention to enable strong, secure and restrained attachment of a pneumatic tire rim to a center body to form an integrated wheel assembly.
It is further an object of the present invention to accomplish such an integration of the tire rim and center body without the need for riveting or resistance and spot welding so as to avoid the air leakages, deterioration and other problems inherent with these previous attachment practices.
It is also an object of the present invention to provide a facilitated and lower cost method of joining the rim to the interior center body, which is especially adaptable to securing a steel rim to a steel center body, while at the same time providing an alternative to convention rim-to-center attachment operation which requires no special alignment of the center body when the center body has an outer peripheral band which is continuous in nature.
These and other objects of the invention will become apparent as set forth herein.